Transconnector for Coupling First and Second Spinal Fixation Elements

ABSTRACT

Transconnector devices and methods of use are provided. A transconnector device has the capability of connecting to elongate spinal fixation elements having various cross-sectional dimensions. The transconnector device is adjustable in three degrees of freedom and is curved to ensure that it maintains a minimum distance posterior of the dura when it is fixed to elongate spinal fixation elements.

FIELD OF THE INVENTION

The present invention relates to the field of surgical implants andmethods, more particularly to spinal implants and surgical methods ousing spinal implants.

BACKGROUND OF THE INVENTION

In the surgical treatment of spinal disorders such as scoliosis,numerous systems for attempting to correct such conditions have beendevised. These systems usually include a pair of elongate members,typically either rods or plates, placed posterior-laterally on oppositesides of the vertebral column. Each rod/plate is attached to the spinewith various attachment devices, such as pedicle screws, spinous processhooks, sublaminar hooks and pedicle hooks.

The strength and stability of a dual rod or plate assembly can beincreased by coupling the two rods or plates with a cross-brace ortransconnector which extends across the spine, substantiallyhorizontal/perpendicular to the longitudinal axes of the rods or plate.The simplest situation in which a transconnector can be used occurs whenthe two rods or plates are geometrically aligned. In this case, the tworods or plates are axially parallel to each other, i.e., there is norod/plate convergence or divergence between the rods in themedial-lateral direction, over the extent of the lengths of the rods.Also, the rods/plates have the same orientation and are parallel withrespect to the coronal plane in the anterior-posterior direction, i.e.,the rods/plates are coplanar from a lateral view, and the rods/platesare located at a fixed predetermined distance from one another.

Due to a wide variety of factors, the two rods or plates are rarelygeometrically aligned in clinical situations. There are several ways toaddress variations from geometrical alignment. One way is to bend one orboth of the rods or plates to accommodate its fixation by thetransconnector. However, bending performed in either of the rods orplates is not always possible to achieve and can adversely affect thefixation thereof to the pedicle screws or hooks, etc. that are fixed tothe spine, and can compromise the clinical outcome of the surgery.Furthermore, the bending can also adversely affect the mechanicalproperties of the rods/plates. Additionally or alternatively, thetransconnector can be bent to address the geometrical misalignment ofthe rods/plates, so that the disturbance to the rod(s)/plate(s)positioning is minimized However, bending of the transconnector cancompromise the mechanical performance of the transconnector.

Adjustable transconnectors designed to adapt for variations fromgeometrical alignment have been provided. However, these transconnectorsare multi-piece systems that can be difficult to assembly and use in thesurgical environment. Further, there is no guarantee that this type oftransconnector cannot become disassembled, losing one or more pieces,after implantation and closing of the patient. Still further, after suchtransconnectors are implanted (fixed to the rods/plates) there designdoes not take into account the spacing necessary to ensure that theimplant does not engage the dura.

Adjustable connectors of one-piece design that are currently availabledo not allow for wide-range adjustments to compensate for all threemodes in which there may be variation from geometric alignment:convergence or divergence, non-coplanar rods/plates, and variability onrod separation distances, while, at the same time, maintainingseparation from the dura and the spinal cord.

There is a continuing need for transconnectors that are fully adjustableto compensate for all three modes of variation from geometricalalignment of the rods/plates being connected by the transconnector,which transconnectors do not pose a risk of disassembly of multipleparts or pose a challenge of assembling multiple parts, and whichtransconnectors maintain a safe distance, after implantation, from thedura and spinal cord, regardless of the position of the transconnector,the vertebral level where it is used or the span between the tworods/plates that the transconnector is joined to. The present inventionmeets at least all of the above needs.

SUMMARY OF THE INVENTION

A transconnector for coupling first and second elongate spinal fixationelements is provided, including: a first member having a first couplingportion configured and dimensioned to receive one of the first andsecond elongate spinal fixation elements, and a first elongatetransconnector member extending from the first coupling; a second memberhaving a second coupling portion configured and dimensioned to receivethe other of the first and second elongate spinal fixation elements, andan end portion extending from the second coupling; and a joint assemblyjoining the first elongate member with the end portion, the jointassembly having a first configuration that allows translation, axialrotation about an axis along which the translation of the first elongatetransconnector member occurs and rotation about an axis perpendicular tothe axis of the rotation about the translation axis, of the first memberrelative to the second member. The first coupling portion is providedwith a first compression member and the second coupling portion isprovided with a second compression member. At least one of the firstcoupling portion and first compression member and the second couplingportion and second compression member are configured to fix one of thefirst and second elongate spinal fixation elements received by applyinga first compression force thereto when the one of the first and secondelongate spinal fixation elements has a first cross-sectional dimension.At least one of the first coupling portion and first compression memberand the second coupling portion and second compression member areconfigured to fix one of the first and second elongate spinal fixationelements received by applying a second compression force greater thanthe first compression force thereto when the one of the first and secondelongate spinal fixation elements has a second cross sectional dimensionsmaller than the first cross-sectional dimension.

In at least one embodiment, at least one coupling portion is configuredto fix an elongate spinal fixation element having a cross-sectionaldimension in the range of about 5.5 mm to about 6.1 mm.

In at least one embodiment, the elongate spinal fixation element is arod and the cross-sectional dimension is a diameter.

In at least one embodiment, at least one coupling portion is configuredto fix an elongate spinal fixation element having a cross-sectionaldimension in the range of about 5.5 mm to about 6.0 mm.

In at least one embodiment, the elongate spinal fixation element is arod and the cross-sectional dimension is a diameter.

In at least one embodiment, the end portion comprises an openingextending transversely therethrough, and the joint assembly comprises arotational member having an open first end and a closed second endaligned along a longitudinal axis of the rotational member. Therotational member further includes a second opening extendingtransversely through a second end portion of the rotational member, andthe rotational member is received in the opening through the end portionof the second member so that the second opening extends at leastpartially from the second member, wherein the elongate transconnectormember passes through the second opening.

In at least one embodiment, a pin extends transversely through a freeend portion of the elongate transconnector member. The pin is configuredand dimensioned to prevent the elongate transconnector member from beingpulled out of the second opening.

In at least one embodiment, an actuator is received in the rotationalmember. The actuator is configured and dimensioned to be actuated toplace the joint assembly in a first configuration that permits thetranslation, axial rotation about an axis of translation and rotationabout an axis perpendicular to the axis of translation, and the actuatoris also actuatable to place the joint assembly in a second configurationthat prevents the translation, axial rotation about an axis oftranslation and rotation about an axis perpendicular to the axis oftranslation.

In at least one embodiment, a locking feature is configured anddimensioned to prevent the actuator from being removed from therotational member.

In at least one embodiment, the first elongate transconnector member iscurved relative to a longitudinal axis of the first member.

In at least one embodiment, the second member comprises a secondelongate transconnector member interconnecting the second couplingportion and the an end portion, and the second elongate transconnectormember is curved relative to a longitudinal axis of the second member.

A transconnector for coupling first and second elongate spinal fixationelements is provided that includes: a first member having a firstcoupling portion configured and dimensioned to receive one of the firstand second elongate spinal fixation elements, and a first elongatetransconnector member extending from the first coupling; a second memberhaving a second coupling portion configured and dimensioned to receivethe other of the first and second elongate spinal fixation elements, andan end portion extending from the second coupling; and a joint assemblyjoining the first elongate member with the end portion, the jointassembly having a first configuration that allows translation, axialrotation about an axis of translation of the first elongatetransconnector member and rotation about an axis perpendicular to theaxis of translation of the first elongate transconnector member, of thefirst member relative to the second member. The joint assembly has asingle actuator actuatable to place the joint assembly in a firstconfiguration that permits the translation, axial rotation about an axisof translation and rotation about an axis perpendicular to the axis oftranslation. The single actuator is also actuatable to place the jointassembly in a second configuration that prevents the translation, axialrotation about an axis of translation and rotation about an axisperpendicular to the axis of translation. A first locking member isconfigured and dimensioned to prevent the first member fromdisconnecting from the joint assembly. A second locking member isconfigured and dimensioned to prevent the single actuator fromdisconnecting from the joint assembly.

In at least one embodiment, the first and second members are curved sothat, when the first coupling portion is fixed to the one of the firstand second elongate spinal fixation elements and the second couplingportion is fixed to the other of the first and second spinal fixationelements, the joint assembly maintains a position spaced posterior of adura of the patient and a position more posterior than positions of thefirst and second coupling portions.

In at least one embodiment, the first coupling portion faces away fromthe joint assembly and the second coupling portion faces away from thejoint assembly.

In at least one embodiment, one of the first and second couplingportions faces away from the joint assembly and the other of the firstand second coupling portions faces toward the joint assembly.

A surgical method is provided that includes: attaching a first elongatespinal fixation element along one side of a spinal column of a patient;attaching a second elongate spinal fixation element along an oppositeside of the spinal column; contacting a transconnector to the first andsecond elongate spinal fixation elements, wherein the transconnectorcomprises a first member having a first coupling portion configured anddimensioned to receive one of the first and second elongate spinalfixation elements, a first elongate transconnector member extending fromthe first coupling; a second member having a second coupling portionconfigured and dimensioned to receive the other of the first and secondelongate spinal fixation elements, an end portion extending from thesecond coupling; and a joint assembly joining the first elongate memberwith the end portion; allowing the transconnector to self adjust as thefirst and second coupling members receive the first and second elongatespinal fixation members, wherein adjusting movement capabilities includetranslation, axial rotation about an axis of translation of the firstelongate transconnector member and rotation about an axis perpendicularto the axis of translation of the first elongate transconnector member,of the first member relative to the second member; and after thetransconnector has self adjusted, locking the joint assembly viaactuation of a single actuator, wherein the locking prevents thetranslation, the axial rotation about an axis of translation and therotation about an axis perpendicular to the axis of translation.

A surgical method is provided that includes: attaching a first couplingportion of a transconnector device to a first elongate spinal fixationelement fixed along one side of a spinal column of a patient; andattaching a second coupling portion of the transconnector device to asecond elongate spinal fixation element fixed along an opposite side ofthe spinal column; wherein the first elongate spinal fixation element,at a location where the first coupling portion is attached has a firstcross-sectional dimension and the second elongate spinal fixationelement, at a location where the second coupling portion is attached hasa second cross-sectional dimension, and wherein the firstcross-sectional dimension is greater than the second cross-sectionaldimension.

In at least one embodiment, the first cross-sectional dimension is about6.0 mm and the second cross-sectional dimension is about 5.5 mm.

In at least one embodiment, the first cross-sectional dimension is afirst diameter and the second cross-sectional dimension is a seconddiameter.

A surgical method is provided that includes: detaching a couplingportion of a transconnector device fixed to a first elongate spinalfixation; and attaching the coupling portion of the transconnectordevice to a second elongate spinal fixation element; wherein the firstelongate spinal fixation element, at a location where the couplingportion is detached from has a first cross-sectional dimension and thesecond elongate spinal fixation element, at a location where thecoupling portion is attached to has a second cross-sectional dimension,and wherein the first cross-sectional dimension is less than the secondcross-sectional dimension.

These and other advantages and features of the invention will becomeapparent to those persons skilled in the art upon reading the details ofthe devices and methods as more fully described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a transconnector device according to anembodiment of the present invention.

FIG. 1B is a longitudinal sectional view of a transconnector deviceaccording to an embodiment of the present invention.

FIG. 1C illustrates a pin inserted through an opening in a member of atransconnector device according to an embodiment of the presentinvention.

FIG. 2 illustrates a first member of a transconnector device accordingto an embodiment of the present invention.

FIG. 3 illustrates a second member of a transconnector device accordingto an embodiment of the present invention.

FIG. 4A is a perspective view of a rotational member of a transconnectordevice according to an embodiment of the present invention.

FIG. 4B is a plan view of the rotational member of FIG. 4A.

FIG. 4C is a longitudinal sectional view taken along 4C-4C of FIG. 4B.

FIG. 4D is a top view of a rotational member of a transconnector deviceaccording to an embodiment of the present invention.

FIG. 5A is a perspective view of an actuator of a transconnector deviceaccording to an embodiment of the present invention.

FIG. 5B is a longitudinal sectional view of the actuator of FIG. 5A.

FIG. 6A is a perspective view of a compression member of atransconnector device according to an embodiment of the presentinvention.

FIG. 6B is a longitudinal sectional view of the compression member ofFIG. 6A.

FIG. 6C is a detail view taken within circle 6C in FIG. 6B.

FIG. 7A is a partial sectional view of a coupling portion of atransconnector device fixed to an elongate spinal fixation elementhaving a first cross-sectional dimension.

FIG. 7B a partial sectional view of the coupling portion of FIG. 7Afixed to a second elongate spinal fixation element having a secondcross-sectional dimension less than the first cross-sectional dimensionof the first element illustrated in FIG. 7A.

FIG. 8 is a longitudinal sectional view of a transconnector deviceaccording to another embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of a transconnector deviceaccording to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Before the present devices and methods are described, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present invention will be limited only by the appendedclaims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin the invention. The upper and lower limits of these smaller rangesmay independently be included or excluded in the range, and each rangewhere either, neither or both limits are included in the smaller rangesis also encompassed within the invention, subject to any specificallyexcluded limit in the stated range. Where the stated range includes oneor both of the limits, ranges excluding either or both of those includedlimits are also included in the invention.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methodsand materials are now described. All publications mentioned herein areincorporated herein by reference to disclose and describe the methodsand/or materials in connection with which the publications are cited.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “ascrew” includes a plurality of such screws and reference to “the rod”includes reference to one or more rods and equivalents thereof known tothose skilled in the art, and so forth.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present invention isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

Referring now to the drawings in detail, FIG. 1 shows a transconnectordevice 10 according to an embodiment of the present invention.Transconnector 10 is configured and dimensioned for coupling first andsecond elongated spinal fixation elements having been attachedposterior-laterally to opposite sides of the spinal column.Transconnector device 10 can be made from any suitable biocompatible,rigid materials typically used in orthopedic implant devices, such astitanium, titanium alloy, stainless steel, or other biocompatible, rigidmetal. Most components of device 10 (with the possible exception of pin90) may alternatively be made from rigid polymer or polymer compositesuch as carbon fibers-filled polyetheretherketone (PEEK). Preferably, atleast the portions of transconnector that make contact with theelongated spinal fixation elements are made of the same material as usedto make the elongated spinal fixation elements or from implant grade,inert, polymer or polymer composite to avoid galvanic corrosion. Thefirst and second elongate spinal fixation elements that can be joined bytransconnector 10 can be cylindrical rods, rectangular bars, plates, orany other device suitable for spinal fusion. As noted, in use, the firstelongate spinal fixation element extends along one side of the vertebralcolumn and the second elongate spinal fixation element extends along theother side of the vertebral column. A wide variety of attachment devicessuch as hooks, screws and clamps can be used to attach the first andsecond elongate spinal fixation elements to the spine.

Transconnector 10 includes a first member 10 having a first couplingportion 22 configured and dimensioned to receive one of the first andsecond elongate spinal fixation elements. A first elongatetransconnector member 24 extends from the first coupling portion 22.

A second member 40 of the transconnector 10 includes a second couplingportion 42 configured and dimensioned to receive the other of the firstand second elongate spinal fixation elements. The second member 40 isfurther provided with an end portion 44 extending from the secondcoupling portion 42. A second elongate transconnector member 46interconnects the second coupling portion 42 and the end portion 44. Inalternative embodiments, the first and second elongate transconnectormembers 24 and 46 may be made shorter or longer than those provided inthe embodiment of FIG. 1A, to provide varying ranges of adjustabilityfor distances between the first and second elongate spinal fixationelements. For example, the distance/space between elongate spinalfixation elements will typically be less where attached to the thoracicportion of the spine compared to the distance/space between elongatespinal fixation elements where attached to the lumbar portion of thespine. Additionally, even spaces in the same relative spinal locationwill vary from patient to patient, particularly when comparing childrento adults and females to males. Thus, in addition to the adjustabilityprovided by each individual transconnector 10, sets of transconnectors10 having first and/or second elongate transconnector members, 24, 46 ofvarying length are provided to even further extend the ranges ofdistances between elongate spinal fixation elements that can be coupledto.

Transconnector 10 further includes a joint assembly 60 that connectsfirst elongate member 24 with end portion 44. By turning actuator 62 inone rotational direction, the joint assembly 60 can be placed in a firstconfiguration that allows translation (i.e., along the directions shownby arrow 70 in FIG. 1A), axial rotation about an axis along which thetranslation of the first elongate transconnector member 24 occurs (inthe directions shown by arrow 72 in FIG. 1A) and rotation about an axisperpendicular to the axis of rotation about the translation axis (in thedirections shown by arrow 74 in FIG. 1A). By turning actuator 62 in theopposite rotational direction, the joint assembly 60 can be placed in alocked configuration that prevents translation, axial rotation about theaxis along which the translation of the first elongate transconnectormember 24 occurs and rotation about the axis perpendicular to the axisof rotation about the translation axis.

As shown in the longitudinal sectional view of transconnector 10 in FIG.1B, joint assembly 60 includes a rotational member 64 that is insertedinto an opening 48 of second member 40. Opening 48 extends transverselythrough the end portion 44 of second member 40 (e.g. see FIG. 3). Anactuator 62 such as a cap screw or other threaded actuator is turnedinto an open end 76 of rotational member 64 having mating threads, asshown in FIG. 1B. In addition to the open end 76 (see FIG. 4A) ofrotational member 64, rotational member 64 has a closed end 78.Opening/open end 76 and closed end 78 are aligned with the longitudinalaxis L-L of rotational member 64, as shown in FIG. 4A. Rotational member64 further includes a second opening 80 extending transversely throughthe side walls of a second end portion of the rotational member, whereinthe second end portion is near the closed end 78, as shown in FIG. 4A.

As noted above, rotational member 64 is received in opening 48 andactuator 62 is threaded into open end 76. Additionally, at least aportion of second opening 80 extends the second member 40 and firstelongate transconnector member 24 passes through the second opening 80as shown in FIGS. 1A-1B. A locking feature 90 is provided to prevent thefirst elongate transconnector 24 from being completely removed out ofthe opening 80 of rotational member 64. This greatly simplifies the useof the transconnector 10 during a surgical procedure, as personnel arenot required to assemble the transconnector device 10. This alsofunction as a safety feature, as there is substantially no risk ofmember 20 becoming disconnected from joint 60 and member 40.

In the embodiment shown in FIGS. 1A-1B, the locking feature comprises apin 90 that passes transversely through and is fixed with respect to theend portion of first elongate transconnector member 24. Pin 90 may bepress fit through a transverse opening 92 through member 24, orotherwise fixed in position so that opposite ends of pin 90 extend fromopposite sides of opening 92/member 24. Pin 90 may include surfaceroughness 94 such as knurling or the like, to increase friction betweenpin 90 and member 24 when pin 90 is fixed by a press fit/friction fit.Pin 90 has a length that is greater than the diameter of opening 80, sothat the ends that protrude from both sides of the member 24 cannot passthrough the opening 80, as illustrated in FIG. 1C. Thus, elongate member24 is prevented from being pulled completely out of opening 80 andprevented from being disconnected from rotational member 64.

FIG. 4B is an elevation view of rotational member 64, FIG. 4C is alongitudinal sectional view taken along 4C-4C in FIG. 4B, and FIG. 4D isa top view of the rotational member 64 of FIG. 4A. As shown in FIGS. 4Band 4C, the outside walls of rotational member 64 include recessed orslotted portions 82, which form shoulders or ledges 84 protruding infrom the inner walls of rotational member, as shown in FIG. 4A.Shoulders/ledges 84 may be deformed inwardly by compressing the slottedportions 82 together using pliers, pinchers or other type of compressiontool. FIG. 4B illustrates shoulder/ledges 84 in an undeformedconfiguration, where the distance between the shoulders/ledges 84 isrepresented by 83. FIG. 4D illustrates shoulder/ledges 84 in a deformedconfiguration, where the distance between the shoulders/ledges 84 isrepresented by 85 and where distance 85 is less than distance 83.

As noted previously, the longitudinally oriented opening which opening76 leads into is provided with threads 86 that mate with thread 96 ofactuator 62. The largest outside diameter of threads 96 is shown as 93in FIG. 5B. Distance 93 is greater than distance 85 but less thandistance 83. Actuator 62 further includes a head 99 that has an outsidediameter that is greater than the inside diameter 79 of opening 76. Aneck portion 98 is formed between head 99 and threads 96. Neck portion98 has an outside diameter 95 that is less than distance 85. Uponassembly (note that joint assembly 60 is completely assembled prior toreceipt by the surgeon or other end user), actuator 62 is threaded intorotational member 64 through opening 76 while shoulders/ledges 84 are inthe undeformed configuration, being separated by distance 83. Thus,since distance 83 is greater than distance 93, the actuator 62 can befreely threaded into the rotational member. The actuator is threaded inuntil the top most thread is below the bottom surfaces of theshoulders/ledges 84. Then the shoulders/ledges 84 are deformed bycompression of the slotted portion 82 so that shoulders/ledges are onlyseparated by a distance 85. Since distance 85 is less than distance 93,actuator is locked/prevented from being rotated completely out of therotational member 64 so as to be separated therefrom. This greatlysimplifies the use of the transconnector 10 during a surgical procedure,as personnel are not required to assemble the transconnector device 10.This also function as a safety feature, as there is substantially norisk of actuator 62 becoming disconnected from rotational member 64 anddevice 10.

Neck portion 88 has sufficient length (spacing between bottom surface ofhead 99 and top-most thread 96) to allow a full range of motion of theactuator 62 turning in the threads 86, to both lock and unlock the jointassembly as described in more detail below. Since the neck portion 98has an outside diameter 95 less than distance 85, it can rotate andtranslate freely relative to shoulders/ledges 84 and the actuator 62 istorqued to move up and down relative to rotational member 64.

When loosely assembled, in an unlocked configuration, first elongatetransconnector member 24 can rotate within and relative to opening 80 ofrotational member 64. Thus, if one of the elongate spinal fixationelements at a location to be joined by device 10 has a longitudinal axisthat extends at an angle α₁ relative to the coronal plane of the patient(i.e., the plane which divides the body in half from front to back) andthe other of the elongate spinal fixation elements at a location to bejoined by device 10 has a longitudinal axis that extends at an angle α₂relative to the coronal plane of the patient, then relative rotation ofcomponents 40 and 20 can take place in direction 72 to adjust the axesC₁ and C₂ to be collinear with (i.e., at angles α₁ and α₂ to the coronalplane respectively) the respective elongate spinal fixation elements tobe coupled to. This allows the coupling members 22, 42 to be coupled tothe elongate spinal fixation elements without the need to bend eitherfixation element or the transconnector 10.

Additionally, first elongate transconnector member 24 can be pushed orpulled (translated) through opening 80 to either decrease or increasethe distance between members 22 and 42, respectively. This featureallows the transconnector 10 to be readily adjusted for differentpatient anatomies (sizes) and used in different regions of the spine.For example, the lumbar vertebrae are typically larger than the thoracicvertebrae, As a result, the distance between fixation elements in thelumbar region would be greater than the distance between the fixationelements in the thoracic regions. Because the length of the firstelongate transconnector member 24 that extends through and beyondopening 80 of rotational member 64 can be changed, the transconnector 10can be adjusted for use in different spinal regions without the need tobend either fixation element or the transconnector 10. As noted above,in order to further increase the adjustability of the transconnector 10,the length of one or both of the first and second elongatetransconnector members 24, 46 can be manufactured in different sizes.

Still further, rotational member 64 can rotate within opening 48 toallow a change in the angle between first elongate transconnector member24 and second elongate transconnector member 46 in a plane perpendicularto the longitudinal axis L-L of rotational member 64.

Actuator 62 can be torqued to draw the rotational member 64 further upinto the end portion 44/48. This can be continued until member 24 isdrawn against the bottom surface of end portion 44 with sufficientcompression force to prevent member 24 from any ability to translate orrotate in any of the directions previously described, i.e., toimmobilize member 24 relative to member 46. Likewise, this also preventsrotational member 62 from rotating, as it is locked in position relativeto end member 44. A tool interface 97 is formed into the top face of thehead 99, see FIG. 5A, for receiving the working end of a driving toolused to turn the actuator 62.

The structure of the coupling portions 22, 42 will depend on thestructure of the elongate spinal fixation elements to be coupled to. Forexample, if the elongate spinal fixation elements are elongate plates,then coupling portions 22, 42 are configured and dimensioned to receiveand clamp elongate plates, by providing the coupling portions with ashape that mates with the elongate plates, such as channel-shapedclamps, for example. As another example, if the elongate spinal fixationelements are elongate cylindrical rods, then coupling portions 22, 42are each provided with a hook shape, as illustrated in the figures. Thecoupling portions 22, 42 further each include a threaded hole 110 (FIGS.1A-1B and 2-3) and a compression member 120 (FIG. 6A) having threads 122that mate with threads 112 of coupling portions 22, 42. In theembodiment shown in FIG. 6A, compression member 120 comprises a setscrew.

Threads 122 and compression member 120, as well as threads 112 aredimensioned and configured so that coupling portions 22, 42 can coupleto rods having varying diameters, such as rods having diameters in therange of about 5.5 mm to about 6.1 mm, typically in the range of about5.5 mm to about 6.0 mm. Likewise, if coupling portions are configured tocouple to elongate elements other than rods, coupling portions areconfigured and dimensioned to couple to elements having cross-sectionaldimensions in the range of about 5.5 mm to about 6.1 mm, typically inthe range of about 5.5 mm to about 6.0 mm.

As best seen in FIG. 6A, compression member 120 has a first end with atool interface 124 formed therein for receiving the working end of adriving tool used to turn the compression member 120, a threadedcylindrical first body portion 126 and a tapered (typically, conicallytapered) second body portion 128. The curved portion of each couplingportion 22, 42 has a radius of curvature that is greater than a radiusof curvature of an elongate spinal fixation element to be coupled to. Asa result, the only contact between coupling portion 22, 42 and thefixation elements 150, 150′ is at a region near the tip portion 23, 43(see FIGS. 1B, 7A and 7B). Furthermore, the only contact betweencompression member 120 and the fixation element 150, 150′ is on thetapered second body portion 128 (see FIGS. 7A-7B). Thus, the fixationelements are clamped between the second body portion 128 and the curvedregion of coupling portion 22, 42 near the tip portion 23, 43.

As noted, device 10 is configured and dimensioned to couple to elongatespinal fixation elements of varying cross-sectional dimensions. It isnoted that, in order to successfully couple (clamp to and fix to preventrelative motion between coupling portion and elongate spinal fixationelement) coupling portion 22, 42 to an elongate spinal fixation element150, 150′, there is a minimal threshold amount of compression that mustbe applied to fixation element 150, 150′ by coupling portion 22, 42(i.e., between the curved surface of coupling portion 22, 42 and thetapered portion 128 of compression member 120). It is further noted thatthe minimal threshold amount of compression required increases as thecross-sectional dimension of the elongate spinal fixation elementdecreases. Accordingly, the threads 112 and 122 must be designed toaccommodate the increase in forces required for fixing a relativelysmaller (cross sectional dimension) fixation element as well as afixation element having a relatively larger cross-sectional dimension.The decision to use a particular rod/plate size/system can be made orchanged intra-operatively. For example, a surgeon may change a 5.5 mmrod to be implanted and decide to rather us a 6.0 mm rod if correctionof a rigid scoliosis condition cannot be maintained by 5.5 mm rods. Inthis case, the surgeon would not need to change out transconnectordevices 10, as devices 10 can couple to 6.0 mm rods as well as to 5.5 mmrods, as noted. Likewise, for surgical revisions, a surgeon may want tochange one or more elongate spinal fixation elements to element(s)having a different cross-section dimension. When changing from a 5.5 mmcross-sectional dimension to a 6.0 mm cross-section dimension, or viceversa, of either one or both elongate spinal fixation elements, anytransconnector devices 10 used to join the original elongate spinalfixation elements would also be capable of joining the new arrangementsof elongate spinal fixation elements.

As another example, there are situations where a surgeon needs to extendthe results of a fusion procedure previously performed, whether theextension is placed either superiorly or inferiorly (or both) of theoriginal elongate spinal fixation elements to correct a secondary orcompensatory deformity that has developed after the original fusionprocedure was performed. In many of these cases different diameter rods(or plates or other elongate members having a different cross-sectionaldimension) are used to extend the original construct. Due to theparticular anatomy of a patient's spine, the type of deformity/pathologyand/or difficulty in inserting a rod-to-rod connector at a particularside/level, the surgeon may need to connect the elongate spinal fixationelements at a different level on one side than at the level connected toon the other side. In such a situation, two different elongate spinalfixation element sizes may be present in the same vertebral level. Inthis case, transconnector 10 can be used to connect the elongate spinalfixation elements at that vertebral level, for example, when oneelongate spinal fixation element has a cross-sectional dimension ofabout 5.5 mm and the other elongate spinal fixation element has across-sectional dimension of about 6.0 mm.

In still another application of the present invention, although notperformed as frequently today, surgeons would previously attempt tocorrect some spinal deformities by implanting one elongate spinalfixation element only, and would revise these cases later if needed.Historically, revisions of such cases have frequently been needed. In acase of this type, if a surgeon is provided with transconnectors 10 ofthe present invention, the surgeon may decide to leave the originalelongate spinal fixation element in place and add a second elongatespinal fixation element on the other side of the vertebrae, and thesecond elongate spinal fixation element may have a differentcross-sectional dimension than that of the first elongate spinalfixation element. Transconnector 10 could then be used to couple to boththe first and second elongate spinal fixation elements. As one example,the first elongate spinal fixation element could be a rod having adiameter of about 5.5 mm and the second spinal fixation element could bea rod having a diameter of about 6.0 mm.

For example, in the embodiment shown in FIG. 7A, the coupling portion 22and compression member 120 are designed to couple to an elongate spinalfixation element 150 having a diameter of about 6 mm. It is noted thatalthough the examples shown in FIGS. 7A-7B are illustrated usingcoupling portion 22, that this disclosure applies equally to use ofcoupling portion 42. Accordingly, when coupling portion 22 has beencoupled to element 150 with sufficient compression force (e.g., about8.0 Nm to fix the components together with sufficient force required toprevent relative movements therebetween during use, the end of thecompression member 120 having the tool interface 124 is flush with thecoupling portion 22, see FIG. 7A.

However, with the same embodiment applied to an elongate spinal fixationelement 150′ having a diameter of about 5.5 mm (see FIG. 7B), whencoupling portion 22 has been coupled to element 150′ with sufficientcompression force to fix the components together with sufficient forcerequired to prevent relative movements therebetween during use, the endof the compression member 120 having the tool interface 124 is recessedwithin the coupling portion 22, see FIG. 7B. As noted above, the element150′ having the smaller cross-sectional dimension requires a greatercompression force to successfully fix to it. In the case of the 5.5 mmrod it has been found that a compression force of at least about 8.5 Nmmust be applied. A still further demand is made upon the threads 112,122 by the fact that the threads of the compression member do not matewith the top thread 112 of the threads 112 of the coupling portion, asshown in FIG. 7B. This also means that a bottom thread 122 ofcompression member 120 is not engaged with a mating thread 112.Accordingly, the remaining threads 112, 122 that are engaged mustwithstand additional forces, not only for the increased amount ofoverall compression that must be applied, but also for the fact that theoverall compression forces are divided by a fewer number of matingthreads.

Accordingly, the design of a device 10 that can accommodate the couplingto elongate spinal fixation elements having varying cross-sectionaldimensions must be provided with robust threads 112, 122 that canaccommodate the increased forces that will be applied thereto. In theembodiment shown in FIG. 6B, threads 122 are buttress threads. It isnoted that although the examples of threads described here are withregard to threads 122 of the compression member 120, that threads 112will be correlated to this design features, as they must mate withthreads 122. The overall length of compression member 120 in thisembodiment is about 7.0 mm to about 7.5 mm, typically about 7.3 mm. Theangle 121 of taper of second body portion 128 relative to thelongitudinal axis L2-L2 of compression member 120 is about thirtydegrees to about sixty degrees, typically about thirty-five to fiftydegrees, more typically about forty degrees. The pitch 123 (see detailedillustration in FIG. 6C) of threads 122 (and therefore also of threads112 is in the range of about 0.7 mm to about 1.2 mm, typically about 1.0mm. The leading flank angle or thread angle 125 of threads 122 (and alsoof threads 112) is about forty degrees to about sixty-five degrees,preferably about fifty-five degrees. The trailing flank angle 127between the top of a buttress thread and the horizontal is about zerodegrees to about fifteen degrees, typically about seven degrees. Theinside diameter of the threads may be about 4.0 mm and the outsidediameter of the threads may be about 6.0 mm. In one embodiment, theinside diameter of threads 122 was about 4.5 mm and the outside diameterwas about 5.8 mm, although, as noted, each of these diameters may vary.

Another important feature of transconnector 10 is its curvature relativeto the coronal plane when installed in a patient, i.e., coupled to twoelongate spinal fixation elements. This curvature 170 (see FIG. 1B)defined by a curved line passing through the centers from which theradii of curvature are measured for the coupling portions 22 and 42, andintersecting the bottom most point of the closed end 78 of rotationalmember 64, is sufficient to ensure that the bottom end 78 of rotationmember does not contact the dura once device 10 has been installed.Preferably, the radii of curvature are designed so that the bottom end78 is never less than about 12.0 mm above the dura when installed in anyconfiguration that the device is capable of being placed in. In order toaccomplish this, first elongate transconnector member 24 is curved,relative to the longitudinal axis L3-L3 of first member 20, as shown inFIG. 2. This curvature can range from about thirty degrees to aboutseventy degrees, and is typically in the range of about forty-fivedegrees and about 64.5 degrees. Likewise, second elongate transconnectormember 46 can be curved, relative to the longitudinal axis L4-L4 ofsecond member 40, as shown in FIGS. 1B and 3. This curvature can rangefrom about thirty degrees to about fifty degrees, and is typically inthe range of about 30.7 degrees to about 53.9 degrees. The curvature 170will vary depending upon the span (distance) between 22 and 42, andresults from the specific radii of curvature of members 20 and 40.Preferably, the angles 171, 173 where the line of curvature 170intersects the horizontal line 175 (e.g., see FIG. 1B) are never lessthan about thirty degrees and are typically in the range of about thirtydegrees to about sixty degrees.

FIG. 8 is a longitudinal sectional view of a transconnector device 10′according to another embodiment of the present invention. Thisembodiment is configured to couple to elongate spinal fixation elementsthat are separated by a shorter distance (inter-fixation elementdistance), relative to the inter-fixation element distances that thedevice 10 of FIGS. 1A-1B is designed for.

Accordingly, all elements are substantially the same as intransconnector 10 except for the first and second elongatetransconnector elements 24′, 46′, which are shorter than the respectiveelements 24, 46.

The embodiment of FIG. 9 is configured and dimensioned to couple withelongate spinal fixation elements having an even smaller range ofinter-fixation element distances than those for which the embodiment ofFIG. 8 is designed for. In this regard, the first and second elongatetransconnector elements 24″, 46″ are shorter than the respectiveelements 24′, 46′. Another difference in transconnector 10″ from thetransconnectors 10 and 10′ of FIGS. 1B and 8, is that both couplingportions 22, 42 of device 10 and both coupling portions 22, 42 of device10′ faces away from the joint assembly 60. That is, the openings of thehook portions of coupling portions 22, 42 face away from the center ofthe device, i.e., away from the joint assembly 60. In the device 10″ ofFIG. 9, however, one of the hooks (in FIG. 9, it is the hook of couplingportion 42) faces toward the joint assembly 60 while the other of thehooks faces away from the joint assembly. Alternative to the arrangementshown in FIG. 9, the hook of portion 22 could face toward the jointassembly and the hook of portion 42 could face away from the jointassembly. In either of these arrangements, this allows the device 10″ tobe installed into a relatively smaller inter-fixation element distancethan would be possible with a device having all the same components asdevice 10″ but where both hook portions face away from the jointassembly.

All of the embodiments described herein simplify methods of implantationby the surgeon relative to prior art transconnectors. The fact that thedevices 10, 10′, 10″ are preassembled and cannot be accidentallydisassembled relieves and requirement of assembling the device by thesurgical team, and ensures that the device remains integrated during theimplantation procedure.

One the elongate spinal fixation elements have been successfullyimplanted according to any known techniques currently used for suchimplantation, device 10, 10′ or 10″, is next installed. Additionally,the device is in the configuration where translation and the two degreesof rotation described above are permitted. Accordingly, the surgeon canthen place one of the coupling portions to receive one of the elongatespinal fixation elements, and place the other one of the couplingportions to receive the other of the elongate spinal fixation elements.Optionally, the compression members 120 can be turned into the portions22, 42 to snugly contact the spinal fixation elements at this time, butthey are not yet torqued down to perform the fixation. The ability totranslate the first and second members 20, 40 relative to one anotherallows adjustment of the inter-fixation element distance, while therelative rotatability of the first and second members allows thecoupling portions 22, 42 to be readily fitted to the fixation elements,without the need to bend the fixation elements or the transconnectordevice. Accordingly, the transconnector device is allowed to“self-adjust” via these translation and rotation movements responsive tocontacting the coupling portions to receive the elongate fixationelements. Once the coupling portions have been fitted to the fixationelements (and optionally “snugged” in place), actuator 62 is nexttorqued down to lock the transconnector in the appropriate configurationand prevent any further translations or rotations of first member 20relate to second member 40. Then the coupling members 22, 42 are fixedto the fixation elements, by torquing compression members 120 to atleast the minimum threshold compression force required to complete thefixation. This completes the installation of the transconnector to thefixation elements.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processstep or steps, to the objective, spirit and scope of the presentinvention. All such modifications are intended to be within the scope ofthe claims appended hereto.

1-20. (canceled)
 21. A transconnector for coupling first and secondelongate spinal fixation elements, said transconnector comprising: afirst member having a first coupling portion and a first elongatetransconnector member extending from said first coupling portion; asecond member having a second coupling portion and an end portionextending from said second coupling portion; a joint assembly joiningsaid first elongate transconnector member with said end portion, saidjoint assembly comprising a rotational member configured to be slidablyreceived in said end portion such that a portion of said rotationalmember extends from a side of said end portion and has an openingconfigured to receive said first elongate transconnector member; anactuator configured to mate with said rotational member and actuatableto lock said transconnector in a desired configuration; a first lockingfeature configured to prevent said first elongate transconnector memberfrom separating from said opening; and a second locking featureconfigured to prevent said actuator from separating from said rotationalmember.
 22. The transconnector of claim 21, wherein in a firstconfiguration, said joint assembly allows translation and axial rotationof said first elongate transconnector member, as well as rotation ofsaid first elongate transconnector member about an axis perpendicular toan axis of rotation about which said axial rotation occurs.
 23. Thetransconnector of claim 21, wherein at least one of said first andsecond coupling portions is configured to fix an elongate spinalfixation element having a cross-sectional dimension in the range ofabout 5.5 mm to about 6.1 mm.
 24. The transconnector of claim 23,wherein said at least one of said first and second coupling portions isconfigured to fix an elongate spinal fixation element having across-sectional dimension in the range of about 5.5 mm to about 6.0 mm.25. The transconnector of claim 21, wherein said first elongatetransconnector member is curved relative to a longitudinal axis of saidfirst member.
 26. The transconnector of claim 21, wherein said secondelongate transconnector member is curved relative to a longitudinal axisof said second member.
 27. The transconnector of claim 25, wherein saidsecond elongate transconnector member is curved relative to alongitudinal axis of said second member.
 28. The transconnector of claim21, wherein said actuator consists of a single actuator.
 29. Thetransconnector of claim 21, wherein in a second configuration, saidjoint assembly prevents translation and axial rotation of said firstelongate transconnector member, as well as rotation of said firstelongate transconnector member about an axis perpendicular to an axis ofrotation about which said axial rotation occurs.
 30. The transconnectorof claim 29, wherein in said second configuration, said joint assemblyprevents movement of said second elongate transconnector member relativeto said first elongate transconnector member.
 31. The transconnector ofclaim 21, wherein said second locking feature comprises shoulders orledges protruding in inner walls of said rotational member,
 32. Thetransconnector of claim 21, wherein said actuator rotates, but does nottranslate relative to said rotational member.
 33. The transconnector ofclaim 21, wherein both of said first and second coupling portions faceaway from said joint assembly.
 34. The transconnector of claim 21,wherein one of said first and second coupling portions faces away fromsaid joint assembly, and the other of said first and second couplingportions faces toward said joint assembly.
 35. A method of operating atransconnector, comprising: providing the transconnector comprising afirst member having a first coupling portion and a first elongatetransconnector member extending from said first coupling portion; asecond member having a second coupling portion and an end portionextending from said second coupling portion; a joint assembly joiningsaid first elongate transconnector member with said end portion, saidjoint assembly comprising a rotational member configured to be slidablyreceived in said end portion such that a portion of said rotationalmember extends from a side of said end portion and has an openingconfigured to receive said first elongate transconnector member; and anactuator configured to mate with said rotational member and actuatableto lock said transconnector in a desired configuration; orienting saidfirst member in a desired orientation relative to said second member byperforming a least one of translating, axially rotating and rotatingabout an axis perpendicular to an axis of said axially rotating saidfirst member relative to said second member; and actuating said actuatorto lock the desired orientation, wherein said actuator rotates, but doesnot translate relative to said rotational member during said actuating.36. The method of claim 35, wherein said orienting comprises allowingsaid transconnector to self-adjust relative to first and second elongatespinal fixation elements.
 37. The method of claim 35, wherein saidtransconnector is fixed to first and second spinal fixation elements.38. The method of claim 37, wherein one of said first and second spinalfixation elements has a cross-sectional dimension in a location ofattachment to said transconnector of about 6 mm and the other of saidfirst and second spinal fixation elements has a cross sectionaldimension in a location of attachment to said transconnector of about5.5 mm.